RA-AF characteristics of acoustic emission in uniaxial compression failure of different bedded coal

Abstract

In order to study the characteristics of RA-AF of coal failure in different coal bedding, uniaxial compression failure experiments of coal with 0°, 30°, 60° and 90° bedding angles were carried out. The mechanical and AE data of coal body were collected synchronously. The relationship between the characteristics of RA-AF and crack propagation mode was analyzed. The results show that: in the Ⅰ and Ⅱ stages, the AE count level is low, in the Ⅲ stage, the AE count is gradually increased, in the Ⅳ stage, when α=0° and 60°, AE counts are more and the peak value is higher; when α=0° and 90°, the tensile failure ratio is 58.44% and 58.06%, respectively, and the tensile failure is the main crack; when α=30°, tensile failure and shear failure are the same, and the crack appears as tensile shear composite failure; when α=60°, the shear failure ratio of the sample is 68.14%, and the shear failure is the main crack.

Keywords

• coal bedding
• acoustic emission
• ra-af characteristics
• uniaxial compression failure
• crack propagation mode